Hybrid air conditioning system

Abstract

To aim to reduce an emission amount of carbon dioxide due to an air-conditioning operation of a hybrid air conditioning system.SOLUTION: A hybrid air conditioning system 10 comprises an engine 20, a motor generator 21, compressors 22a, 22b actuated by a driving force of at least one of the engine 20 and the motor generator 21, and a control device 15 for controlling the engine 20 and the motor generator 21. The control device 15 controls the engine 20 and the motor generator 21, so that the compressors 22a, 22b are actuated by a driving force of the engine 20 in an engine preferential time zone during which a carbon dioxide emission coefficient of fuel is smaller than that of power, and the compressors 22a, 22b are actuated by a driving force of the motor generator 21 in a motor preferential time zone during which the carbon dioxide emission coefficient of power is determined to be equal to or less than that of fuel, when an operation mode is a carbon dioxide emission-saving mode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a hybrid air conditioning system that uses an engine and a motor as driving power sources. [Background technology]

[0002] Patent Document 1 discloses a hybrid air conditioning system that uses both an engine and a motor to drive the compressor. The hybrid air conditioning system disclosed in Patent Document 1 sets the engine to either rated operation or stopped. During rated operation, the engine's surplus power drives the generator, and when stopped, the motor drives the compressor. Furthermore, if the air conditioning operation becomes overloaded during rated operation, the motor assists in driving the compressor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-272134 Summary of the Invention

[0004] (Problem to be solved by the invention) According to the hybrid air conditioning system described in Patent Document 1, the engine load is adjusted by driving (generating electricity) a generator to maximize engine efficiency. The electricity generated by the generator is charged into a battery, and when the air conditioning load is low, the battery power or the grid power supply is used to drive the motor and operate the compressor. In this way, when the engine is running, it only operates at its rated speed, achieving high engine efficiency.

[0005] However, in today's social climate, efforts to reduce carbon dioxide emissions are becoming increasingly important, and simply achieving high engine efficiency is not enough to fully meet social needs.

[0006] In view of the above circumstances, one of the objects of the present disclosure is to provide a hybrid air conditioning system that can contribute to reducing carbon dioxide emissions.

[0007] (Means for solving the problem) The hybrid air conditioning system according to this embodiment includes: a refrigerant circuit including an indoor heat exchanger and an outdoor heat exchanger; an engine that generates driving force when fuel is supplied; a motor that generates driving force when supplied with power from a power system; a compressor that is operated by at least one of the driving force of the engine and the driving force of the motor, and that causes a refrigerant to circulate through the refrigerant circuit by operating; a control device that controls the engine and the motor, A hybrid air conditioning system including a carbon dioxide emission saving mode in an operation mode that reduces the amount of carbon dioxide emitted by using the fuel or the electricity, When the operating mode is the carbon dioxide emission saving mode, the control device controls the engine and the motor according to the time of day so that the compressor operates using the driving force of the engine during an engine priority time period, which is a time period during a day when it is determined that the carbon dioxide emission coefficient of the fuel is smaller than the carbon dioxide emission coefficient of the electricity, and so that the compressor operates using the driving force of the motor during a motor priority time period, which is a time period during a day when it is determined that the carbon dioxide emission coefficient of the electricity is equal to or smaller than the carbon dioxide emission coefficient of the fuel.

[0008] The hybrid air conditioning system according to the present invention preferentially uses either the engine or the motor, whichever has a lower carbon dioxide emission coefficient, as the driving power source for the compressor, thereby reducing carbon dioxide emissions compared to when such control is not performed. Therefore, a hybrid air conditioning system that can contribute to reducing carbon dioxide emissions can be provided. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a hybrid air conditioning system. [Figure 2] Figure 2 is a table showing carbon dioxide emission factors. [Figure 3] FIG. 3 is a flowchart illustrating an example of processing executed by the control device. [Figure 4] FIG. 4 is a flowchart illustrating an example of processing executed by the control device. [Figure 5] FIG. 5 is a flowchart illustrating an example of processing executed by the control device. [Figure 6] FIG. 6 is a flowchart illustrating an example of processing executed by the control device. [Figure 7] FIG. 7 is a flowchart illustrating an example of processing executed by the control device. [Figure 8] FIG. 8 is a flowchart illustrating an example of processing executed by the control device. [Figure 9] FIG. 9 is a flowchart illustrating an example of processing executed by the control device. [Figure 10] FIG. 10 is a diagram illustrating an example of the configuration of a power transmission mechanism. [Figure 11] FIG. 11 is a diagram illustrating an example of the configuration of a power transmission mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0010] A hybrid air conditioning system according to an embodiment of the present invention will be described below. In the following description, the "hybrid air conditioning system" may be abbreviated as "air conditioning system."

[0011] FIG. 1 is a diagram showing the configuration of an air conditioning system 10. As shown in FIG. 1, the air conditioning system 10 includes one outdoor unit 11 disposed outside a room to be air-conditioned (such as a building in which the air conditioning system 10 is installed), a predetermined number (two indoor units 12 are shown as an example in FIG. 1) of indoor units 12 disposed inside the room to be air-conditioned, and a refrigerant circuit 13 provided across the outdoor unit 11 and the indoor unit 12. The outdoor unit 11 is provided with a power unit 14, a control device 15, a battery 16, and an outdoor heat exchanger 17. The indoor unit 12 is provided with an indoor heat exchanger 18. The power unit 14 includes one engine 20, one motor-generator 21, two compressors 22a, 22b (first compressor 22a and second compressor 22b), and a power transmission mechanism 23.

[0012] The engine 20 is a driving power source for the two compressors 22a, 22b. The engine 20 is also a driving power source for the motor generator 21 when the motor generator 21, which will be described later, operates as a generator. A gas engine is used as the engine 20. The engine 20 is connected to a gas supply source (for example, a city gas distribution facility) external to the air conditioning system 10, and outputs driving power (rotational power) by operating using gas supplied from the gas supply source as fuel.

[0013] The motor generator 21 is an example of a motor and a generator motor according to the present invention. The motor generator 21 functions as a driving force source for two compressors 22a and 22b (described later) and as a generator that generates electricity using the driving force output by the engine 20. The motor generator 21 is electrically connected to a system power supply and a battery 16. When functioning as a motor (driving force source), the motor generator 21 operates (outputs driving force) using power supplied from the system power supply or power supplied from the battery 16. When functioning as a generator, the motor generator 21 can charge the generated power to the battery 16. In the following description, unless otherwise specified, the operation / stop of the motor generator 21 refers to the operation / stop of the motor generator 21 as a motor (in other words, as a driving force source).

[0014] The two compressors 22a, 22b, that is, the first compressor 22a and the second compressor 22b, include input shafts 221a, 221b, respectively, and are configured to operate when a driving force is input to the input shafts 221a, 221b, and to circulate a refrigerant through the refrigerant circuit 13. Both of the two compressors 22a, 22b are operated (driven) by a driving force output from at least one of the engine 20 and the motor generator 21. Both of the two compressors 22a, 22b include a refrigerant suction port 222 and a refrigerant discharge port 223, and are configured to draw in a refrigerant through the refrigerant suction port 222, compress the drawn refrigerant, and discharge it from the refrigerant discharge port 223. The refrigerant suction port 222 and the refrigerant discharge port 223 of the compressors 22a, 22b are connected to the refrigerant circuit 13 (it can also be said that each of the two compressors 22a, 22b forms a part of the refrigerant circuit 13). The configuration of the compressors 22a and 22b is not particularly limited, and a conventionally known configuration can be applied.

[0015] The power transmission mechanism 23 is configured to be able to transmit the driving force output by the engine 20 to the two compressors 22a, 22b. The power transmission mechanism 23 is also configured to be able to transmit the driving force output by the motor generator 21 when it functions as a motor to the two compressors 22a, 22b. The power transmission mechanism 23 is also configured to be able to transmit the driving force output by the engine 20 to the motor generator 21. For example, the power transmission mechanism 23 includes a gear provided on the output shaft 201 of the engine 20, a gear provided on the rotating shaft 211 of the motor generator 21, and gears provided on the input shafts 221a, 221b of the two compressors 22a, 22b, respectively, and these gears are linked to each other so as to be able to transmit power.

[0016] A clutch (hereinafter referred to as EG shaft clutch 235) is provided on the output shaft 201 of the engine 20. Clutches (hereinafter referred to as CP shaft clutches 236a and 236b) are also provided on the input shafts 221a and 221b of the two compressors 22a and 22b, respectively. The EG shaft clutch 235 and the two CP shaft clutches 236a and 236b are both configured to be switchable between a "state that permits power transmission" (hereinafter referred to as an "on-state") and a "state that does not permit power transmission" (hereinafter referred to as a "disconnected state"). The configurations of the EG shaft clutch 235 and the two CP shaft clutches 236a and 236b are not particularly limited, and conventional electromagnetic clutches or the like can be applied.

[0017] When the EG shaft clutch 235 and the two CP shaft clutches 236a, 236b are in the engaged state, the two compressors 22a, 22b can be operated by the driving force of the engine 20. When the EG shaft clutch 235 is in the engaged state, one of the two CP shaft clutches 236a, 236b is in the engaged state, and the other of the two CP shaft clutches 236a, 236b is in the disengaged state, one of the two compressors 22a, 22b can be operated by the driving force of the engine 20 while the other cannot be operated. Furthermore, when the EG shaft clutch 235 is in the disengaged state, when the motor generator 21 operates as a driving force source for the compressors 22a, 22b, the driving force of the motor generator 21 can be prevented from being transmitted to the engine 20.

[0018] The battery 16 is electrically connected to the motor generator 21 and the system power supply. The battery 16 can be charged with power supplied from the system power supply and can also be charged with power generated by the motor generator 21. The battery 16 can also supply operating power to each part of the air conditioning system 10, including the power unit 14 and the control device 15.

[0019] The control device 15 is a device that controls each part of the air conditioning system 10, including the power unit 14. The control device 15 is equipped with a computer that includes a CPU, ROM, RAM, a storage device, and an I / F (interface). A computer program for controlling each part of the air conditioning system 10 and each threshold value described below are stored in advance in the ROM or storage device of the computer of the control device 15. The CPU of the computer of the control device 15 then reads this computer program from the ROM or storage device, expands it in RAM (using the RAM as a work area), and executes it. At this time, the CPU of the computer of the control device 15 appropriately references each threshold value, etc. In this way, control of the air conditioning system 10 is realized.

[0020] The refrigerant circuit 13 includes an indoor heat exchanger 18, an outdoor heat exchanger 17, a four-way valve 42, and a refrigerant path 41. The indoor heat exchanger 18 is configured to exchange heat between the refrigerant flowing therethrough and the indoor air. The outdoor heat exchanger 17 is configured to exchange heat between the refrigerant flowing therethrough and the outdoor air. The refrigerant path 41 is a path configured to allow the refrigerant to flow therethrough.

[0021] The four-way valve 42 includes a first port 421, a second port 422, a third port 423, and a fourth port 424. The four-way valve 42 is configured to be able to selectively realize a first state and a second state. In the first state, the first port 421 and the second port 422 communicate with each other, and the third port 423 and the fourth port 424 communicate with each other. In the second state, the first port 421 and the third port 423 communicate with each other, and the second port 422 and the fourth port 424 communicate with each other.

[0022] The indoor heat exchanger 18, the outdoor heat exchanger 17, and the four-way valve 42 are connected to one another by a refrigerant path 41. It can also be said that the indoor heat exchanger 18, the outdoor heat exchanger 17, and the four-way valve 42 are provided on the refrigerant path 41. The refrigerant path 41 includes a discharge path 411 that connects a first port 421 of the four-way valve 42 to the refrigerant discharge ports 223 of the two compressors 22a, 22b, a suction path 412 that connects a fourth port 424 of the four-way valve 42 to the refrigerant suction ports 222 of the two compressors 22a, 22b, and a heat exchanger path 413 that connects the second port 422 and the third port 423 of the four-way valve 42. The indoor heat exchanger 18 and the outdoor heat exchanger 17 are provided on the heat exchanger path 413, in that order from the side closest to the second port 422.

[0023] <Air conditioning operation of the air conditioning system> Next, we will explain the basic operation of the air conditioning system 10. The air conditioning operation of the air conditioning system 10 includes heating operation and cooling operation. The four-way valve 42 is set to a first state during heating operation and to a second state during cooling operation.

[0024] Heating operation is as follows: At least one of the two compressors 22a, 22b is operated by the driving force of at least one of the engine 20 and the motor generator 21, thereby drawing in low-temperature, low-pressure gas-phase refrigerant in the suction path 412 through the refrigerant suction port 222, compressing it, and discharging the high-temperature, high-pressure gas-phase refrigerant from the refrigerant discharge port 223. The refrigerant discharged from the refrigerant discharge port 223 passes through the discharge path 411 and flows into the first port 421 of the four-way valve 42.

[0025] When the four-way valve 42 is in the first state, the refrigerant (high-temperature, high-pressure refrigerant) that flows from the discharge path 411 into the first port 421 of the four-way valve 42 flows out of the four-way valve 42 through the second port 422, passes through the heat exchanger path 413, and flows into the indoor heat exchanger 18 of the indoor unit 12. The refrigerant that flows into the indoor heat exchanger 18 releases heat into the room in the indoor heat exchanger 18 (exchanges heat with the indoor air), and a portion of the refrigerant condenses.

[0026] The refrigerant that has passed through the indoor heat exchanger 18 passes through the heat exchanger path 413 and flows into the outdoor heat exchanger 17. Then, the refrigerant that has flowed into the outdoor heat exchanger 17 exchanges heat with the outdoor air (removes heat from the outdoor air) and is partially vaporized. The partially vaporized refrigerant passes through the heat exchanger path 413 and flows into the third port 423 of the four-way valve 42.

[0027] The refrigerant that flows from the heat exchanger passage 413 into the third port 423 of the four-way valve 42 flows out from the fourth port 424, passes through the suction passage 412, and flows into the refrigerant suction ports 222 of the compressors 22a and 22b. This refrigerant circulation cycle is repeated, thereby continuing the room heating.

[0028] Cooling operation is as follows: As in heating operation, high-temperature, high-pressure gas-phase refrigerant is discharged from the refrigerant discharge ports 223 of the compressors 22a and 22b, and the discharged refrigerant flows into the first port 421 of the four-way valve 42. The refrigerant that flows into the first port 421 of the four-way valve 42 from the discharge path 411 flows out from the third port 423, passes through the heat exchanger path 413, and flows into the outdoor heat exchanger 17. Then, the refrigerant (high-temperature, high-pressure gas-phase refrigerant) that flows into the outdoor heat exchanger 17 releases heat to the outside air (exchanges heat with the outside air) while passing through the interior thereof, and a portion of it condenses.

[0029] The refrigerant that has passed through the outdoor heat exchanger 17 flows into the indoor heat exchanger 18 of the indoor unit 12 through the heat exchanger path 413. The refrigerant that has flowed into the indoor heat exchanger 18 absorbs heat from the indoor air while passing through there and evaporates (exchanges heat with the indoor air). This cools the indoor air, and the room is cooled. The refrigerant that has passed through the indoor heat exchanger 18 flows into the second port 422 of the four-way valve 42 through the heat exchanger path 413.

[0030] The refrigerant that has flowed into the second port 422 of the four-way valve 42 flows out from the fourth port 424 and flows into the refrigerant suction ports 222 of the compressors 22a and 22b through the suction path 412. This refrigerant circulation cycle is repeated to continue cooling the room.

[0031] A conventionally known refrigerant circuit can be applied to the refrigerant circuit 13. For example, the refrigerant circuit disclosed in JP 2021-18007 A can be applied. Therefore, a detailed description of the configuration of the refrigerant circuit 13 will be omitted. The air conditioning system 10 may also include a coolant circuit such as that disclosed in JP 2021-18007 A.

[0032] <Specific operation of the air conditioning system> Next, a specific operation of the air conditioning system 10 will be described. The air conditioning operation of the air conditioning system 10 includes four operating modes: a carbon dioxide emission reduction mode, a hybrid mode, an engine mode, and a power generation mode. These four operating modes are alternatively selectable. When the supply of power from the grid power supply and the supply of gas from an external source are continuous, the air conditioning system 10 can perform air conditioning operation in one operating mode selected from these four operating modes. Note that when the supply of power from the grid power supply is stopped but the supply of gas from an external source is continuous, the air conditioning system 10 can perform air conditioning operation in the engine mode or the power generation mode.

[0033] (Carbon dioxide emission reduction mode) The carbon dioxide reduction mode is an operating mode that reduces the amount of carbon dioxide emitted through the use of gas and electricity. Of the four operating modes, the carbon dioxide reduction mode produces the least amount of carbon dioxide. For this reason, the carbon dioxide reduction mode is an ideal operating mode when prioritizing the reduction of carbon dioxide emissions.

[0034] The control device 15 compares the carbon dioxide emission coefficient of the system power supply with the carbon dioxide emission coefficient of the gas. If the carbon dioxide emission coefficient of the system power supply is equal to or less than the carbon dioxide emission coefficient of the gas, the control device 15 prioritizes the use of the motor generator 21 as the driving power source for the compressors 22a, 22b. On the other hand, if the carbon dioxide emission coefficient of the system power supply is greater than the carbon dioxide emission coefficient of the gas, the control device 15 prioritizes the use of the engine 20 as the driving power source for the compressors 22a, 22b.

[0035] There are two types of carbon dioxide emission coefficients for a grid power supply: a total power coefficient and a marginal coefficient. In this embodiment, the control device 15 changes whether to use the total power coefficient or the marginal coefficient depending on the time of day. FIG. 2 is a table showing an example of the relationship between the time of day and the carbon dioxide emission coefficient of the grid power supply used by the air conditioning system 10. In this embodiment, the total power coefficient is used as the carbon dioxide emission coefficient for the grid power supply during the time periods of 0:00 to 16:00 and 21:00 to 24:00. On the other hand, the marginal coefficient is used as the carbon dioxide emission coefficient for the grid power supply during the time periods of 16:00 to 21:00. The time period of 16:00 to 21:00 is an example of a first time period in the present invention, and the time periods of 0:00 to 16:00 and 21:00 to 24:00 are examples of a second time period in the present invention. The first time period may include at least a portion of the time period from 16:00 to 21:00, and is not limited to the time period including the entire time period from 16:00 to 21:00.

[0036] The reason for this is as follows: In grid power sources, increased demand for electricity is met by marginal power sources during times of high demand. Marginal power sources include thermal power generation and solar power generation, and as the proportion of thermal power generation to total power generation increases, carbon dioxide emissions increase. During the late night hours of the day, demand for electricity is low, and the proportion of power generation from marginal power sources to total power generation decreases. Furthermore, during the daytime until before sunset, demand for electricity is high, but the proportion of power generation from solar power generation, which emits less carbon dioxide as a marginal power source, increases. On the other hand, during the hours from sunset to night, demand for electricity is high, but power generation from solar power generation is not possible, so the proportion of power generation from thermal power generation, which is a marginal power source, increases.

[0037] For this reason, during the late night hours and the daytime to before sunset, the amount of carbon dioxide emissions from using gas is greater than the amount of carbon dioxide emissions from using electricity from the grid power supply. On the other hand, during the time from sunset to night, the amount of carbon dioxide emissions from using electricity from the grid power supply is greater than the amount of carbon dioxide emissions from using gas. Therefore, by changing the carbon dioxide emission coefficient used depending on the time of day, the amount of carbon dioxide emissions from the air conditioning operation of air conditioning system 10 can be determined in accordance with the actual situation.

[0038] The control device 15 acquires the current time and determines which of the time periods shown in FIG. 2 the current time falls within. In the example shown in FIG. 2, if the current time falls within the time period from 0:00 to 16:00 or 21:00 to 24:00 (i.e., the second time period), the control device 15 compares the total power coefficient, which is the carbon dioxide emission coefficient of the grid power source, with the carbon dioxide emission coefficient of gas. If the current time falls within the time period from 16:00 to 21:00 (i.e., the first time period), the control device 15 compares the marginal coefficient, which is the carbon dioxide emission coefficient of the grid power source, with the carbon dioxide emission coefficient of gas. If the carbon dioxide emission coefficient of the grid power source is equal to or less than the carbon dioxide emission coefficient of gas, the control device 15 determines that the current time falls within the "motor priority time period." On the other hand, if the carbon dioxide emission coefficient of the grid power source is greater than the carbon dioxide emission coefficient of gas, the control device 15 determines that the current time falls within the "engine priority time period."

[0039] The carbon dioxide emission coefficient of the system power supply and the carbon dioxide emission coefficient of the gas are stored in advance in the storage device of the computer of the control device 15. In this case, the control device 15 is configured to be able to store the carbon dioxide emission coefficient of the system power supply and the carbon dioxide emission coefficient of the gas in the storage device through operation by a user, etc. The control device 15 may also obtain the carbon dioxide emission coefficient of the system power supply and the carbon dioxide emission coefficient of the gas from equipment external to the air conditioning system 10 via an I / F.

[0040] Furthermore, the time zone divisions shown in Fig. 2 are merely an example, and are not limited to the time zone divisions shown in Fig. 2. For example, since the hours of daylight vary depending on the season, the time zone divisions may be changed depending on the season.

[0041] When the control device 15 determines that the current time falls within the motor priority time period, it prioritizes the use of the motor generator 21 as the driving power source for the compressors 22a and 22b. Then, the control device 15 switches between operating only the motor generator 21 and operating both the motor generator 21 and the engine 20 according to the air conditioning load. The control device 15 also switches between operating only one of the two compressors 22a and 22b and operating both of the two compressors 22a and 22b according to the air conditioning load.

[0042] Specifically, when the control device 15 determines that the current time falls within the motor priority time slot and the air conditioning load is low, it operates the motor generator 21 but does not operate the engine 20. At this time, the control device 15 disengages the EG shaft clutch 235 so that the driving force of the motor generator 21 is not transmitted to the engine 20. The control device 15 also engages one of the two CP shaft clutches 236a, 236b and disengages the other. This allows one of the two compressors 22a, 22b to operate using the driving force of the motor generator 21. On the other hand, when the control device 15 determines that the current time falls within the motor priority time slot and the air conditioning load is high, it operates the motor generator 21 and the engine 20. At this time, the control device 15 engages the EG shaft clutch 235. The control device 15 also engages both of the two CP shaft clutches 236a, 236b. As a result, both of the two compressors 22a and 22b are operated by the driving force of the motor generator 21 and the engine 20.

[0043] When the control device 15 determines that the current time falls within the engine priority time zone, it prioritizes the use of the engine 20 as the driving power source for the compressors 22a and 22b. Then, the control device 15 switches between operating only the engine 20 and operating both the engine 20 and the motor generator 21 according to the air conditioning load. Also, the control device 15 switches between operating only one of the two compressors 22a and 22b and operating both of the two compressors 22a and 22b according to the air conditioning load.

[0044] Specifically, when the control device 15 determines that the current time falls within the motor priority time slot and the air conditioning load is low, it operates the engine 20 and stops the motor generator 21. At this time, the control device 15 connects the EG shaft clutch 235. The control device 15 also connects one of the two CP shaft clutches 236a, 236b and disconnects the other. As a result, one of the two compressors 22a, 22b operates using the driving force of the engine 20. On the other hand, when the control device 15 determines that the current time falls within the engine priority time slot and the air conditioning load is high, it operates the engine 20 and the motor generator 21. At this time, the control device 15 connects the EG shaft clutch 235. The control device 15 also connects both of the two CP shaft clutches 236a, 236b. As a result, both of the two compressors 22a, 22b operate using the driving force of the engine 20 and the motor generator 21.

[0045] Thus, in the carbon dioxide emission saving mode, when the carbon dioxide emission coefficient of the grid power supply is equal to or less than the carbon dioxide emission coefficient of the gas, priority is given to using the motor generator 21 as the driving power source for the compressors 22a, 22b. On the other hand, when the carbon dioxide emission coefficient of the grid power supply is greater than the carbon dioxide emission coefficient of the gas, priority is given to using the engine 20 as the driving power source for the compressors 22a, 22b. This allows for a reduction in carbon dioxide emissions compared to when such control is not performed. Therefore, a hybrid air conditioning system 10 that can contribute to a reduction in carbon dioxide emissions can be provided.

[0046] Here, the determination of whether the air conditioning load is high or low will be explained. The control device 15 determines that the air conditioning load is low when a load condition indicating a high air conditioning load is not met, and determines that the air conditioning load is high when the load condition is met. Note that the following, for example, applies to the load condition. When the current room temperature is at or near the target temperature and the control device 15 is performing air conditioning operation with an output that can maintain the room temperature at or near the target temperature, the control device 15 determines that the load condition is not met and the air conditioning load is low. On the other hand, when the current room temperature is far from the target temperature and the control device 15 is performing air conditioning operation with an output that can bring the room temperature closer to the target temperature (note that this output is greater than the output that can maintain the room temperature at or near the target temperature), the control device 15 determines that the load condition is met and the air conditioning load is high.

[0047] In addition, the control device 15 may calculate the thermal load of the air-conditioned object using a known calculation method, and if the calculated thermal load is less than a predetermined threshold, determine that the load conditions are not met and the air-conditioning load is low, and if the calculated thermal load is equal to or greater than the threshold, determine that the load conditions are met and the air-conditioning load is high.

[0048] Furthermore, the control device 15 may determine that the load condition is not met and that the air conditioning load is low when the indoor temperature can be maintained at the set temperature by operating only one of the two compressors 22a, 22b, and may determine that the load condition is met and that the air conditioning load is high when the indoor temperature cannot be maintained at the set temperature by operating only one of the two compressors 22a, 22b (in other words, when the air conditioning capacity is insufficient unless both compressors 22a, 22b are operated). In this case, the control device 15 compares the air conditioning capacity of the air conditioning system 10 when only one of the two compressors 22a, 22b is operating with the thermal load of the air-conditioning target. Then, if the air conditioning capacity is equal to or greater than the thermal load, the control device 15 determines that the load condition is not met and that the air conditioning load is low, and if the air conditioning capacity is less than the thermal load, the control device 15 determines that the load condition is met and that the air conditioning load is high.

[0049] (Hybrid mode) The hybrid mode is an operating mode in which both the engine 20 and the motor generator 21 can be used as the driving power sources for the compressors 22a and 22b, and is the operating mode in which the amount of electricity consumed from the grid power supply can be the greatest among the four modes. The hybrid mode is an operating mode suitable for cases where priority is given to energy consumption efficiency (when increased energy consumption efficiency is desired). Note that "energy consumption efficiency" is the ratio of air conditioning capacity to energy consumption. The hybrid mode further includes three sub-modes: an efficiency priority mode, a fuel saving priority mode, and a power saving priority mode. When in the hybrid mode, the control device 15 alternatively selects one of these three sub-modes.

[0050] (Efficiency priority mode) The efficiency priority mode is a sub-mode that prioritizes energy consumption efficiency. In the air conditioning system 10 according to this embodiment, the energy consumption efficiency is higher when the motor generator 21 is operated than when the engine 20 is operated. Therefore, in the efficiency priority mode, the use of the motor generator 21 is prioritized over the use of the engine 20 as the driving power source for the two compressors 22a, 22b. That is, when the control device 15 determines that the air conditioning load is low, it operates only the motor generator 21, and when it determines that the air conditioning load is high, it operates both the motor generator 21 and the engine 20.

[0051] Specifically, when the control device 15 determines that the air conditioning load is low, it operates the motor generator 21 but does not operate the engine 20. The control device 15 also operates one of the two compressors 22a, 22b. In this case, the control device 15 connects one of the two CP shaft clutches 236a, 236b and disengages the other of the two CP shaft clutches 236a, 236b and the EG shaft clutch 235. On the other hand, when the control device 15 determines that the air conditioning load is high, it operates both the motor generator 21 and the engine 20 and operates both the two compressors 22a, 22b. In this case, the control device 15 switches all of the two CP shaft clutches 236a, 236b and the EG shaft clutch 235 to the connect state.

[0052] When both the engine 20 and the motor generator 21 are operated, the control device 15 controls the rotation speed of the engine 20 so that the rotation speed of the engine 20 approaches a target rotation speed. The control device 15 also controls the rotation speed of the motor generator 21 so that the rotation speed of the motor generator 21 is synchronized with the rotation speed of the engine 20. Furthermore, the control device 15 controls the drive torque of the motor generator 21 so that the load on the engine 20 is maximized (so that the efficiency of the engine 20 reaches its peak).

[0053] In the efficiency priority mode, the control device 15 can operate the engine 20 and the motor generator 21 to achieve high energy consumption efficiency. The efficiency priority mode is a sub-mode that prioritizes the use of the motor generator 21. Therefore, similar to the fuel-saving priority mode, the amount of gas used can be reduced. On the other hand, when the control device 15 determines that the air-conditioning load is high in the efficiency priority mode, the control device 15 additionally operates the engine 20 and drives both compressors 22a and 22b. That is, in the efficiency priority mode, the control device 15 does not operate the two compressors 22a and 22b using the driving force of the motor generator 21 alone. Therefore, when the air-conditioning load is determined to be high, the load on the motor generator 21 can be reduced and the engine 20 and the motor generator 21 can be operated in a state of high energy consumption efficiency. In particular, when both the engine 20 and the motor generator 21 are operated, the control device 15 controls the driving torque of the motor generator 21 so that the efficiency of the engine 20 reaches its peak. Therefore, the energy consumption efficiency of the air-conditioning system 10 can be improved.

[0054] (Fuel saving priority mode) The fuel saving priority mode is a sub-mode that prioritizes reducing the amount of gas used. In the fuel saving priority mode, the use of the motor generator 21 as the driving power source for the compressors 22a and 22b is prioritized over the use of the engine 20. That is, the control device 15 operates only the motor generator 21 as long as the driving power of the motor generator 21 is sufficient, and operates both the motor generator 21 and the engine 20 when the driving power of the motor generator 21 is insufficient.

[0055] Specifically, when the control device 15 determines that the air-conditioning load is low, it operates the motor generator 21 and one of the two compressors 22a, 22b. That is, the control device 15 connects one of the two CP shaft clutches 236a, 236b and disengages the other of the two CP shaft clutches 236a, 236b and the EG shaft clutch 235. Furthermore, when the control device 15 determines that the air-conditioning load is high (or has become high), it operates the motor generator 21 and both of the two compressors 22a, 22b. That is, the control device 15 connects both of the CP shaft clutches 236a, 236b and disengages the EG shaft clutch 235. Furthermore, when the driving force of the motor generator 21 is insufficient while the driving force of the two compressors 22a, 22b is being driven by the driving force of the motor generator 21, the control device 15 operates the engine 20 while continuing to operate the motor generator 21. In this case, the control device 15 puts all of the two CP shaft clutches 236a, 236b and the EG shaft clutch 235 into the connected state.

[0056] Here, a method for determining whether the driving force of the motor generator 21 is insufficient will be described. The control device 15 continuously monitors the driving torque of the motor generator 21 in real time while the motor generator 21 is operating. If the driving torque of the motor generator 21 is less than a predetermined torque threshold, the control device 15 determines that the driving force condition is not met and that the driving force of the motor generator 21 is not insufficient. On the other hand, if the driving torque of the motor generator 21 is equal to or greater than the predetermined torque threshold, the control device 15 determines that the driving force condition is met and that the driving force of the motor generator 21 is insufficient. Note that this threshold is not particularly limited and is set appropriately depending on the specifications of the motor generator 21, etc.

[0057] In this way, in the fuel saving priority mode, priority is given to the specifications of the motor generator 21 as the driving power source for the two compressors 22a and 22b. Therefore, the amount of gas used can be reduced during the air conditioning operation of the air conditioning system 10.

[0058] (Power saving priority mode) The power saving priority mode is a sub-mode that prioritizes reducing power consumption. Therefore, in the power saving priority mode, the use of the engine 20 as the driving power source for the compressors 22a, 22b is prioritized over the use of the motor generator 21. That is, the control device 15 operates only the engine 20 unless the driving power of the engine 20 is insufficient, and operates both the motor generator 21 and the engine 20 when the driving power of the engine 20 is insufficient.

[0059] Specifically, when the control device 15 determines that the air conditioning load is low, it operates the engine 20 and one of the two compressors 22a, 22b. In this case, the control device 15 engages one of the two CP shaft clutches 236a, 236b and the EG shaft clutch 235, and disengages the other of the two CP shaft clutches 236a, 236b. When the control device 15 determines that the air conditioning load is high, it drives both of the two compressors 22a, 22b. In this case, the control device 15 engages both of the two CP shaft clutches 236a, 236b and the EG shaft clutch 235.

[0060] Furthermore, if the control device 15 determines that the driving force of the engine 20 is insufficient while the two compressors 22a, 22b are operating, it operates the motor generator 21. That is, the control device 15 operates both the motor generator 21 and the engine 20. In this case, the control device 15 connects the two CP shaft clutches 236a, 236b and the EG shaft clutch 235. Note that the control of the engine 20 and the motor generator 21 while both the engine 20 and the motor generator 21 are operating is the same as the control in the efficiency priority mode.

[0061] Here, a method for determining whether the driving force of the engine 20 is insufficient will be described. The control device 15 continuously monitors the operating conditions of the engine 20, including at least the engine 20 rotation speed and the opening of the air valve of the mixer (a device that mixes gas and air and supplies the resulting mixture to the engine 20), in real time. When the opening of the mixer's air valve is increased to increase the engine 20's output, if the engine 20 rotation speed increases in response to the increase in the mixer's air valve opening, the control device 15 determines that the driving force condition indicating a driving force insufficiency of the driving force source is not met, and that the driving force of the engine 20 is not insufficient. On the other hand, when the opening of the mixer's air valve is increased to increase the engine 20's output, if the engine 20 rotation speed does not increase in response to the increase in the mixer's air valve opening, the control device 15 determines that the driving force condition indicating a driving force insufficiency of the driving force source is met, and that the driving force of the engine 20 is insufficient.

[0062] In the power saving priority mode, when the driving force of the engine 20 is sufficient, the electric power from the grid power supply is not used, thereby reducing the amount of electric power used. Furthermore, when the driving force of the engine 20 is insufficient, the motor generator 21 is operated additionally, thereby preventing or suppressing a shortage of the driving force of the compressors 22a, 22b. As a result, the air conditioning capacity according to the user's request can be achieved.

[0063] (Engine mode) The engine mode is an operation mode in which the compressors 22a, 22b are driven only by the driving force of the engine 20 (i.e., the motor generator 21 is not used as a driving force source for the compressors 22a, 22b). The engine mode is an operation mode in which the amount of power consumed from the system power supply is the second smallest after the power generation mode described below.

[0064] The control device 15 operates only the engine 20, and switches between operating one of the two compressors 22a, 22b or both of the two compressors 22a, 22b depending on the air-conditioning load. Specifically, when the control device 15 determines that the air-conditioning load is low, it operates one of the two compressors 22a, 22b. In this case, the control device 15 engages one of the two CP shaft clutches 236a, 236b and the EG shaft clutch 235, and disengages the other of the two CP shaft clutches 236a, 236b. On the other hand, when the control device 15 determines that the air-conditioning load is high, it operates both of the two compressors 22a, 22b. In this case, the control device 15 engages both of the two CP shaft clutches 236a, 236b and the EG shaft clutch 235.

[0065] In the engine mode, the power from the grid power supply is not used as a driving power source for the compressors 22a, 22b, so that the amount of power consumed by the grid power supply can be reduced. Note that in the engine mode, even when the air conditioning load is high, the motor generator 21 is not used as a driving power source for the compressors 22a, 22b. Therefore, in the engine mode, when the air conditioning load is high, the amount of power consumed by the grid power supply can be reduced more than in the power saving priority mode of the hybrid mode.

[0066] (Power generation mode) The power generation mode is an operation mode in which the compressors 22a, 22b are operated using only the driving force of the engine 20, and the motor generator 21 is caused to generate electricity. Of the four operation modes, the power generation mode is the operation mode that uses the least amount of power from the grid power supply (it does not consume power from the grid power supply). Therefore, the power generation mode is an operation mode that is suitable when prioritizing reduction in the amount of power used from the grid power supply.

[0067] The control device 15 operates one of the two compressors 22a, 22b by operating only the engine 20. In this case, the control device 15 connects one of the two CP shaft clutches 236a, 236b and the EG shaft clutch 235, and disconnects the other of the two CP shaft clutches 236a, 236b. Furthermore, the control device 15 operates the motor generator 21 as a generator. The control device 15 then charges the battery 16 with electric power generated by the motor generator 21, and operates each component of the air conditioning system 10 using the electric power generated by the motor generator 21.

[0068] In the power generation mode, only the engine 20 is used as the driving power source for the compressors 22a and 22b, which reduces the power consumption of the air conditioning system 10 compared to air conditioning operation that uses the motor generator 21 as the driving power source for the compressors 22a and 22b. Alternatively, the air conditioning system 10 can perform air conditioning operation without using power from the power grid by using the power generated by the motor generator 21 to operate each component. This reduces the load on the power grid.

[0069] (Switching (selecting) driving modes) The air conditioning system 10 is configured so that the user can select one of four operating modes: the carbon dioxide emission saving mode, the hybrid mode, the engine mode, and the power generation mode. For example, the air conditioning system 10 is provided with a circuit (such as a switch) that indicates the current operating mode, and the user can select one of the four operating modes by operating this circuit. The air conditioning system 10 is then configured to perform air conditioning operation in the selected operating mode.

[0070] The air conditioning system 10 may also be configured so that the user can select only whether or not to perform air conditioning operation in the carbon dioxide emission saving mode. If the carbon dioxide emission saving mode is not selected, the air conditioning system 10 may be configured to select one of the engine mode, hybrid mode, and power generation mode depending on the power usage status of the grid power supply, and perform air conditioning operation in the selected operation mode.

[0071] Specifically, when the carbon dioxide emission saving mode is selected, the control device 15 of the air conditioning system 10 performs air conditioning operation in the carbon dioxide emission saving mode. On the other hand, when the carbon dioxide emission saving mode is not selected, the control device 15 of the air conditioning system 10 continuously determines the power usage status of the grid power supply in real time. Then, when the amount of power usage from the grid power supply by the air conditioning target by the air conditioning system 10 is less than a predetermined first threshold, the control device 15 selects the hybrid mode. Furthermore, when the amount of power usage from the grid power supply is equal to or greater than the first threshold and less than a predetermined second threshold, the control device 15 of the air conditioning system 10 selects the engine mode. Furthermore, when the amount of power usage from the grid power supply is equal to or greater than the second threshold, the control device 15 of the air conditioning system 10 selects the power generation mode.

[0072] The first threshold is a value that is sufficiently small relative to the allowable amount of power that the air conditioning target can use (for example, the upper limit of the contracted power or the capacity of the molded-case circuit breaker for the air conditioning target), and is a value that indicates that the air conditioning target has a sufficient margin of remaining power that can be used. The second threshold is a value that is larger than the first threshold and close to the allowable amount of power that the air conditioning target can use, and is a value that indicates that the remaining power that the air conditioning target can use is low (i.e., power is tight). Therefore, it can be said that when the amount of power usage from the grid power supply is less than the first threshold, the level of power tightness of the air conditioning target is low; when the amount of power usage is equal to or greater than the first threshold and less than the second threshold, the level of power tightness of the air conditioning target is medium; and when the amount of power usage is equal to or greater than the second threshold, the level of power tightness of the air conditioning target is high. The first threshold and second threshold are values that are set appropriately depending on the allowable amount of power that the air conditioning target can use and other electrical loads installed in the air conditioning target, and are not limited to specific values.

[0073] In this case, the control device 15 is connected to a power meter of the air conditioning equipment via an I / F and continuously acquires the measured values of the amount of power used by the power meter in real time. The first threshold value and the second threshold value are stored in advance in a storage device of the computer of the control device 15. The control device 15 then uses the acquired measured values to determine the level of power pressure.

[0074] In this way, when the carbon dioxide emission saving mode is not selected, the control device 15 of the air conditioning system 10 selects one of the engine mode, hybrid mode, or power generation mode depending on the power usage status (power pressure level) of the air conditioning target.The air conditioning system 10 then performs air conditioning operation in the selected operation mode.

[0075] This configuration allows for appropriate air conditioning operation according to the user's settings and power usage. When a need to reduce carbon dioxide emissions takes priority, the control device 15 can reduce carbon dioxide emissions by operating the air conditioning in the carbon dioxide-saving mode.

[0076] Specifically, when performing air conditioning operation in the carbon dioxide emission saving mode, the control device 15 prioritizes the use of the motor generator 21 as the driving power source for the compressors 22a and 22b over the use of the engine 20 if the carbon dioxide emission coefficient of the grid power supply is equal to or less than the carbon dioxide emission coefficient of the gas. On the other hand, when the carbon dioxide emission coefficient of the gas is less than the carbon dioxide emission coefficient of the grid power supply, the control device 15 prioritizes the use of the engine 20 as the driving power source for the compressors 22a and 22b over the use of the motor generator 21. This reduces carbon dioxide emissions. Meanwhile, when the air conditioning load is high, both the engine 20 and the motor generator 21 are operated to operate the compressors 22a and 22b. This prevents insufficient air conditioning capacity when the air conditioning load is high, allowing the air conditioning capacity required by the user to be achieved. This allows the air conditioning capacity required by the user to be achieved while reducing carbon dioxide emissions.

[0077] Furthermore, when not in the carbon dioxide emission saving mode, the control device 15 can switch the operation mode depending on the power usage status of the grid power supply (the level of power shortage). That is, when the level of power shortage is low, the control device 15 can perform air conditioning operation in hybrid mode, when the level is medium, the control device 15 can perform air conditioning operation in engine mode, and when the level is high, the control device 15 can perform air conditioning operation in power generation mode.

[0078] The hybrid mode includes a fuel saving priority mode, an efficiency priority mode, and a power saving priority mode. The fuel saving priority mode is a sub-mode that prioritizes reducing gas consumption. Therefore, the fuel saving priority mode can reduce gas consumption. The efficiency priority mode is a sub-mode that prioritizes motor use. Therefore, the gas consumption can be reduced in the same way as the fuel saving priority mode. The power saving priority mode is a sub-mode that prioritizes reducing power consumption. Therefore, the power saving priority mode can reduce power consumption.

[0079] On the other hand, in the hybrid mode, the control device 15 switches between driving either the motor generator 21 or the engine 20, or both the motor generator 21 and the engine 20, depending on the air conditioning load and the driving force load. Furthermore, in the hybrid mode, it is possible to switch between driving one or both of the two compressors 22a, 22b, depending on the air conditioning load and the driving force load. This makes it possible to prevent or suppress insufficient air conditioning capacity, thereby enabling the air conditioning capacity to be achieved according to the user's request.

[0080] In this way, when the grid power supply is at a low level, the control device 15 selects and executes one of the efficiency priority mode, power saving priority mode, and fuel saving priority mode in the hybrid mode, thereby enabling operation with characteristics according to the user's request. Even when the efficiency priority mode is selected, carbon dioxide emissions can be reduced by giving priority to using a grid power supply with a small carbon dioxide emission coefficient. Furthermore, since operation can be performed taking into account the efficiency characteristics of the motor generator 21 and the engine 20, highly efficient operation can be achieved.

[0081] Furthermore, the control device 15 can prevent or suppress an increase in the level of power shortage of the grid power supply by performing air conditioning operation in engine mode when the level of power shortage of the grid power supply is medium. That is, air conditioning operation in engine mode is air conditioning operation that uses only the engine 20 as the driving force for the compressors 22a and 22b. Therefore, power from the grid power supply is not used to drive the compressors 22a and 22b.

[0082] Furthermore, by performing air conditioning operation in the power generation mode when the power shortage level of the grid power supply is high, the control device 15 can significantly reduce its own power load by using the engine 20 as the main driving power source for the compressors 22a, 22b during power shortages, and can also reduce the power load of the grid power supply by generating power with the surplus power of the engine 20. Therefore, compared to air conditioning operation that uses the motor generator 21 as the driving power source for the compressors 22a, 22b, it is possible to reduce the power consumption of the air conditioning system 10, thereby preventing or suppressing the grid power supply from becoming even more constrained.

[0083] <Processing performed by the control device> Next, the processing executed by the computer of the control device 15 will be described. Figures 3 to 9 are flowcharts showing the processing executed by the computer of the control device 15. A computer program for executing these processes is stored in advance in the ROM or storage device of the computer of the control device 15. The CPU of the computer of the control device 15 then reads this computer program from the ROM or storage device, expands it in RAM, and executes it. The CPU repeatedly and continuously executes this series of processes at a predetermined short cycle. This realizes the air conditioning operation described above.

[0084] In step S101, the CPU determines whether the operation mode is set to the carbon dioxide emission saving mode. If the operation mode is set to the carbon dioxide emission saving mode, the CPU executes a carbon dioxide emission saving routine in steps S201 to S216. The carbon dioxide emission saving routine is a routine for performing air conditioning operation in the carbon dioxide emission saving mode. If the operation mode is not the carbon dioxide emission saving mode, the CPU proceeds to step S102.

[0085] In step S102, the CPU determines the level of power pressure. If the level of power pressure is low, the CPU executes a hybrid routine of steps S301 to S334. The hybrid routine is a routine for performing air conditioning operation in hybrid mode. If the level of power pressure is medium, the CPU executes an engine routine of steps S401 to S405. The engine routine is a routine for performing air conditioning operation in engine mode. If the level of power pressure is high, the CPU executes a power generation routine of steps S501 to S505. The power generation routine is a routine for performing air conditioning operation in power generation mode.

[0086] (Carbon dioxide reduction routine) In step S201, the CPU acquires the carbon dioxide emission coefficient of the grid power supply at the current time. If the current time is within the time slot of 0:00 to 16:00 or 21:00 to 24:00, the CPU acquires the total power coefficient as the carbon dioxide emission coefficient, and if the current time is within the time slot of 16:00 to 21:00, the CPU acquires the marginal coefficient as the carbon dioxide emission coefficient. Then, the CPU proceeds to step S202.

[0087] In step S202, the CPU compares the carbon dioxide emission coefficient of the gas with the current carbon dioxide emission coefficient of the grid power supply. If the carbon dioxide emission coefficient of the grid power supply is equal to or less than the carbon dioxide emission coefficient of the gas (if the current time is within the motor priority time period), the CPU proceeds to step S203. If the carbon dioxide emission coefficient of the gas is smaller than the carbon dioxide emission coefficient of the grid power supply (if the current time is within the engine priority time period), the CPU proceeds to step S210.

[0088] In step S203, the CPU determines whether the air conditioning load is high or low. In other words, the CPU determines whether the load condition is met. If the air conditioning load is low (if the load condition is not met), the CPU proceeds to step S204, and if the air conditioning load is high (if the load condition is met), the CPU proceeds to step S207.

[0089] In step S204, the CPU stops the engine 20 and operates the motor generator 21 as a motor. Then, the CPU proceeds to step S205.

[0090] In step S205, the CPU operates the first compressor 22a using the driving force of the motor generator 21 and stops the second compressor 22b. Specifically, the CPU switches the CP shaft clutch 236a of the first compressor 22a to an engaged state and switches the CP shaft clutch 236b of the second compressor 22b to a disengaged state. If the first compressor 22a is operating, the CPU continues the operation of the first compressor 22a (maintains the CP shaft clutch 236a of the first compressor 22a in an engaged state). If the second compressor 22b is stopped, the CPU continues the stop of the second compressor 22b (maintains the CP shaft clutch 236b of the second compressor 22b in a disengaged state). Then, the CPU proceeds to step S206.

[0091] In step S206, the CPU controls the rotation speed of the motor generator 21 so that the rotation speed approaches a predetermined target value (or so that the predetermined target value is maintained), and then temporarily ends this carbon dioxide emission reduction routine.

[0092] In step S207, the CPU operates the engine 20 and the motor generator 21. Then, the CPU advances the process to step S208.

[0093] In step S208, the CPU operates both of the two compressors 22a, 22b using the driving forces of the engine 20 and the motor generator 21. That is, the CPU switches both of the two CP shaft clutches 236a, 236b to the continuous state. Note that if both of the two compressors 22a, 22b are operating, the CPU continues the operation of both of the two compressors 22a, 22b (maintaining both of the two CP shaft clutches 236a, 236b in the continuous state). Then, the CPU proceeds to step 209.

[0094] In step S209, the CPU controls the rotation speed of the engine 20 so that the rotation speed of the engine 20 approaches the target rotation speed (so that the target rotation speed is maintained). The CPU also controls the rotation speed of the motor generator 21 so that the rotation speed of the motor generator 21 is synchronized with the rotation speed of the engine 20. Furthermore, the CPU controls the drive torque of the motor generator 21 so that the drive torque of the motor generator 21 approaches the target torque (so that the target torque is maintained). Then, the CPU temporarily ends the carbon dioxide emission saving routine.

[0095] In step S210, the CPU determines whether the air conditioning load is high or low. If the air conditioning load is low, the CPU proceeds to step S211, and if the air conditioning load is high, the CPU proceeds to step S214.

[0096] In step S211, the CPU operates the engine 20 and stops the motor generator 21. If the engine 20 is operating, the CPU continues operating the engine 20, and if the motor generator 21 is stopped, the CPU continues stopping the motor generator 21. Then, the CPU proceeds to step S212.

[0097] The content of step S212 is the same as the content of step S205. Then, the CPU proceeds to step S213.

[0098] In step S213, the CPU controls the rotation speed of the engine 20 so that the rotation speed of the engine 20 approaches a predetermined target value (or so that the predetermined target value is maintained), and then temporarily ends this carbon dioxide emission reduction routine.

[0099] In step S214, the CPU operates the engine 20 and the motor generator 21. If the engine 20 and the motor generator 21 are operating, the CPU continues their operation. Then, the CPU proceeds to step S215.

[0100] The contents of steps S215 and S216 are the same as the contents of steps S208 and S209, respectively. Then, the CPU temporarily ends the carbon dioxide emission saving routine.

[0101] (Hybrid Routine) In step S301, the CPU determines whether the efficiency priority mode is selected. If the efficiency priority mode is selected, the CPU proceeds to step S302. On the other hand, if the efficiency priority mode is not selected, the CPU proceeds to step S309.

[0102] Steps S302 to S308 are the same as steps S203 to S209 of the carbon dioxide emission saving routine (see FIG. 4), and therefore a description thereof will be omitted.

[0103] In step S309, the CPU determines whether the power saving priority mode is selected. If the power saving priority mode is selected, the CPU proceeds to step S310. If the power saving priority mode is not selected (i.e., if the fuel saving priority mode is selected), the CPU proceeds to step S324.

[0104] In step S310, the CPU determines whether the air conditioning load is high or low. If the air conditioning load is low, the CPU proceeds to step S311, and if the air conditioning load is high, the CPU proceeds to step S314.

[0105] In step S311, the CPU operates the engine 20 and stops the motor generator 21. If the engine 20 is operating, the CPU continues operating the engine 20. If the motor generator 21 is stopped, the CPU continues stopping the motor generator 21. Then, the CPU proceeds to step S312.

[0106] In step S312, the CPU operates the first compressor 22a and stops the second compressor 22b. If the first compressor 22a is operating, the CPU continues operating the first compressor 22a. If the second compressor 22b is stopped, the CPU continues stopping the second compressor 22b. Then, the CPU proceeds to step S313.

[0107] In step S313, the CPU controls the rotation speed of the engine 20 so that the rotation speed of the engine 20 approaches a predetermined target value (or so that the predetermined target value is maintained), and then the CPU temporarily ends this hybrid routine.

[0108] In step S314, the CPU determines whether the motor generator 21 is operating. If the motor generator 21 is not operating, the CPU proceeds to step S315. If the motor generator 21 is operating, the CPU proceeds to step S321.

[0109] In step S315, the CPU operates the engine 20. If the engine 20 is operating, the CPU continues to operate the engine 20. The CPU also continues to stop the motor generator 21. Then, the CPU proceeds to step S316.

[0110] In step S316, the CPU operates both of the two compressors 22a and 22b. If both of the two first compressors 22a and 22b are operating, the CPU continues operating both of the two compressors 22a and 22b. Then, the CPU proceeds to step S317.

[0111] In step S317, the CPU controls the rotation speed of the engine 20 so that the rotation speed of the engine 20 approaches the target rotation speed. Then, the CPU proceeds to step S318.

[0112] In step S318, the CPU determines whether the driving force of the engine 20 is insufficient (whether the driving force condition is met). If the driving force of the engine 20 is not insufficient (if the driving force condition is not met), the CPU temporarily ends this hybrid routine. If the driving force of the engine 20 is insufficient (if the driving force condition is met), the CPU proceeds to step S319.

[0113] In step S319, the CPU operates the motor generator 21 while continuing to operate the engine 20. Then, the CPU proceeds to step S320.

[0114] In step S320, the CPU controls the rotation speed of the motor generator 21 so that the rotation speed of the motor generator 21 is synchronized with the rotation speed of the engine 20. Furthermore, the CPU controls the drive torque of the motor generator 21 so that the drive torque of the motor generator 21 approaches the target torque (so that the target torque is maintained). Then, the CPU temporarily ends the hybrid routine.

[0115] In step S321, the CPU operates the engine 20 and continues the operation of the motor generator 21. Then, the CPU proceeds to step S322.

[0116] In step S322, the CPU operates both of the two compressors 22a, 22b. That is, the CPU switches both of the CP shaft clutches 236a, 236b of the two compressors 22a, 22b to the on state. Note that if both of the two compressors 22a, 22b are operating (if both of the CP shaft clutches 236a, 236b of the two compressors 22a, 22b are in the on state), the CPU continues the operation of both of the two compressors 22a, 22b (maintaining both of the CP shaft clutches 236a, 236b of the two first compressors 22a, 22b in the on state). Then, the CPU proceeds to step S323.

[0117] The content of step S323 is the same as the content of step 209 (see FIG. 4). Then, the CPU temporarily ends the hybrid routine.

[0118] In step S324, the CPU determines whether the air conditioning load is high or low. If the air conditioning load is low, the CPU proceeds to step S325, and if the air conditioning load is high, the CPU proceeds to step S328.

[0119] The contents of steps S325 to S325 are the same as the contents of steps S204 to S206. Then, the CPU temporarily ends this hybrid routine.

[0120] In step S328, the CPU determines whether or not the engine 20 is running. If the engine 20 is not running, the CPU proceeds to step S329. If the engine 20 is running, the CPU proceeds to step S335.

[0121] In step S329, the CPU operates the motor generator 21 while continuing to stop the engine 20. Then, the CPU proceeds to step S330.

[0122] In step S330, the CPU operates both of the two compressors 22a and 22b. If both of the two compressors 22a and 22b are operating, the CPU continues the operation of both of the two compressors 22a and 22b. Then, the CPU proceeds to step S331.

[0123] In step S331, the CPU controls the rotation speed of the motor generator 21 so that the rotation speed of the motor generator 21 approaches the target rotation speed. Then, the CPU proceeds to step S332.

[0124] In step S332, the CPU determines whether the driving force of the motor generator 21 is insufficient (whether the driving force condition is met). If the driving force of the motor generator 21 is not insufficient (if the driving force condition is not met), the CPU temporarily ends the hybrid routine. If the driving force of the motor generator 21 is insufficient (if the driving force condition is met), the CPU proceeds to step S333.

[0125] In step S333, the CPU operates the engine 20 while continuing to operate the motor generator 21. Then, the CPU proceeds to step S334.

[0126] The content of step S334 is the same as the content of step S209. Then, the CPU temporarily ends the hybrid routine.

[0127] In step S325, the CPU operates the motor generator 21 while continuing to stop the engine 20. Then, the CPU proceeds to step S336.

[0128] In step S336, the CPU operates both of the two compressors 22a and 22b. If both of the two compressors 22a and 22b are operating, the CPU continues the operation of both of the two compressors 22a and 22b. Then, the CPU proceeds to step S337.

[0129] The content of step S337 is the same as the content of step S209. Then, the CPU temporarily ends the hybrid routine.

[0130] (engine routine) In step S401, the engine 20 is operated and the motor generator 21 is stopped. If the engine 20 is operating, the CPU continues operating the engine 20. If the operation of the motor generator 21 is stopped, the CPU continues stopping the operation of the motor generator 21. The CPU then proceeds to step S402.

[0131] In step S402, the CPU determines whether the air conditioning load is high or low. If the air conditioning load is low, the CPU proceeds to step S403. If the air conditioning load is high, the CPU proceeds to step S404.

[0132] In step S403, the CPU operates the first compressor 22a and stops the second compressor 22b. If the first compressor 22a is operating, the CPU continues operating the first compressor 22a. If the second compressor 22b is stopped, the CPU continues stopping the second compressor 22b. Then, the CPU proceeds to step S405.

[0133] In step S404, the CPU operates the two compressors 22a and 22b. If the two compressors 22a and 22b are in operation, the CPU continues the operation of the two compressors 22a and 22b. Then, the CPU proceeds to step S405.

[0134] In step S405, the CPU controls the rotation speed of the engine 20 so that the rotation speed of the engine 20 approaches the target rotation speed, and then the CPU temporarily ends the engine routine.

[0135] (Power generation routine) In step S501, the CPU determines whether or not the motor generator 21 is generating electricity. If the motor generator 21 is not generating electricity, the CPU proceeds to step S502. If the motor generator 21 is generating electricity, the CPU proceeds to step S503.

[0136] In step S502, the CPU operates the engine 20 and stops the operation of the motor generator 21. If the engine 20 is operating, the CPU continues the operation of the engine 20. If the motor generator 21 is stopped, the CPU continues the stop of the motor generator 21. Then, the CPU proceeds to step S503.

[0137] In step S503, the CPU operates the first compressor 22a and stops the second compressor 22b. If the first compressor 22a is operating, the CPU continues operating the first compressor 22a. If the second compressor 22b is stopped, the CPU continues stopping the second compressor 22b. Then, the CPU proceeds to step S504.

[0138] In step S504, the CPU starts power generation by the motor generator 21. If power generation by the motor generator 21 is in progress, the CPU continues power generation by the motor generator 21. Then, the CPU proceeds to step S505.

[0139] In step S505, the CPU controls the rotation speed of the engine 20 so that the rotation speed of the engine 20 approaches the target value (so that the target value is maintained), and then the CPU temporarily ends the power generation routine.

[0140] The above-described process realizes air conditioning operation in each of the above-described operation modes. Note that, in the above-described process, a configuration has been shown in which, of the two compressors 22a, 22b, the first compressor 22a is used with priority over the second compressor 22b, but the present invention is not limited to such a configuration. For example, the second compressor 22b may be used with priority over the first compressor 22a. Furthermore, which of the two compressors 22a, 22b is given priority may be changed as appropriate.

[0141] Here, an example configuration of the power transmission mechanism 23 of the power unit 14 will be described. Figures 10 and 11 are schematic diagrams showing the configuration of the power transmission mechanism 23. Note that Figure 10 is a view seen in a direction perpendicular to the output shaft 201 of the engine 20, and Figure 11 is a view seen in a direction parallel to the output shaft 201 of the engine 20. In Figure 11, the outlines of the engine 20, the motor generator 21, and the two compressors 22a, 22b are indicated by dashed lines.

[0142] 10 and 11, the power transmission mechanism 23 includes one EG shaft gear 231, one MG shaft gear 232, two CP shaft gears 233a and 233b (i.e., the same number as the compressors 22a and 22b), one CT gear 234, one EG shaft clutch 235, two CP shaft clutches 236a and 236b (i.e., the same number as the compressors 22a and 22b), a damper 237, and a housing 238. The one MG shaft gear 232, the two CP shaft gears 233a and 233b, and the one CT gear 234 form a gear train that is linked together to transmit driving force. The gears of the power transmission mechanism 23 are rotatably housed in the housing 238.

[0143] The EG shaft gear 231 is a gear provided coaxially on the output shaft 201 of the engine 20. The MG shaft gear 232 is a gear provided coaxially on the rotating shaft 211 of the motor generator 21. The two CP shaft gears 233a and 233b are gears provided coaxially on the input shafts 221a and 221b of the two compressors 22a and 22b, respectively. The CT gear 234 is a counter gear interposed between the EG shaft gear 231 and the two CP shaft gears 233a and 233b. The CT gear 234 is also an idle gear, and is rotatably supported by a housing 238. As shown in FIG. 11 , the EG shaft gear 231 and the MG shaft gear 232 directly mesh, the EG shaft gear 231 directly meshes with the CT gear 234, and the CT gear 234 directly meshes with the two CP shaft gears 233a and 233b.

[0144] Between the EG shaft gear 231 and the main body of the engine 20, a damper 237 and an EG shaft clutch 235 are arranged in this order from the side closest to the main body of the engine 20. Therefore, it can also be said that "the EG shaft gear 231 is attached to the output shaft 201 of the engine 20 via the damper 237 and the EG shaft clutch 235." The damper 237 is a damping device for absorbing vibrations and noise of the engine 20. The configuration of the damper 237 is not limited, but the configurations disclosed in, for example, Japanese Patent Application Laid-Open No. 2012-71731 or Japanese Patent Application Laid-Open No. 2007-16855 can be applied. The EG shaft clutch 235 is configured to be able to interrupt the transmission of power between the engine 20 and the EG shaft gear 231 under the control of the control device 15. The configuration of the EG shaft clutch 235 is not particularly limited, and various electromagnetic clutches can be applied.

[0145] The two CP shaft clutches 236a, 236b are disposed between the CP shaft gears 233a, 233b and the main bodies of the compressors 22a, 22b, respectively. Therefore, it can also be said that "the CP shaft gears 233a, 233b are attached to the input shafts 221a, 221b of the compressors 22a, 22b via the CP shaft clutches 236a, 236b." The two CP shaft clutches 236a, 236b are configured to be able to connect and disconnect the transmission of power between the CP shaft gears 233a, 233b and the main bodies of the compressors 22a, 22b under the control of the control device 15. The configuration of the CP shaft clutches 236a, 236b is not particularly limited, and various electromagnetic clutches can be applied.

[0146] According to this configuration, when the EG shaft clutch 235 is in the engaged state and one of the two CP shaft clutches 236a, 236b is also in the engaged state, one of the two compressors 22a, 22b can be operated by the driving force output by the engine 20. Furthermore, when both the EG shaft clutch 235 and the two CP shaft clutches 236a, 236b are in the engaged state, both of the two compressors 22a, 22b can be operated by the driving force output by the engine 20. Furthermore, when both the engine 20 and the motor generator 21 are operating, the driving forces of the engine 20 and the motor generator 21 can be transmitted to one or both of the two compressors 22a, 22b. Furthermore, because the output of the engine 20 is transmitted to the motor generator 21, electricity can be generated by the driving force of the engine 20.

[0147] Furthermore, when the EG shaft clutch 235 is in a disengaged state and one of the two CP shaft clutches 236a, 236b is in an engaged state, one of the two compressors 22a, 22b can be operated by the driving force output by the motor generator 21. Furthermore, when the EG shaft clutch 235 is in a disengaged state and both of the two CP shaft clutches 236a, 236b are in an engaged state, both of the two compressors 22a, 22b can be operated by the driving force output by the motor generator 21. At this time, when the EG shaft clutch 235 is in a disengaged state, the driving force of the motor generator 21 is not transmitted to the engine 20.

[0148] However, the configuration of the power transmission mechanism 23 is not limited to this. The power transmission mechanism 23 may be configured in any way as long as it can transmit the driving force output by the engine 20 to the two compressors 22a, 22b, can transmit the driving force output by the motor generator 21 when it functions as a motor to the two compressors 22a, 22b, and can transmit the driving force output by the engine 20 to the motor generator 21. The power transmission mechanism 23 may be configured to be switchable between a state in which the driving force of at least one of the engine 20 and the motor generator 21 can be transmitted to one of the two compressors 22a, 22b and a state in which the driving force can be transmitted to both of them.

[0149] <Summary of the embodiment> (1) The hybrid air conditioning system 10 according to this embodiment is a refrigerant circuit 13 including an indoor heat exchanger 18 and an outdoor heat exchanger 17; an engine 20 that generates driving force when fuel is supplied; a motor (motor generator 21) that generates driving force when supplied with power from a system power supply; compressors 22a, 22b that operate using at least one of the driving force of the engine 20 and the driving force of the motor (motor generator 21) and that, when operated, cause a refrigerant to circulate through the refrigerant circuit 13; a control device 15 that controls the engine 20 and the motor (motor generator 21); The operating modes include a carbon dioxide emission saving mode that reduces the amount of carbon dioxide emitted by using the fuel or the electricity.

[0150] When the operating mode is the carbon dioxide emission saving mode, the control device 15 controls the engine 20 and the motor (motor generator 21) according to the time of day so that the compressors 22a, 22b operate using the driving force of the engine 20 during engine priority time periods, which are time periods in a day when it is determined that the carbon dioxide emission coefficient of the fuel is smaller than the carbon dioxide emission coefficient of the electricity, and so that the compressors 22a, 22b operate using the driving force of the motor (motor generator 21) during motor priority time periods, which are time periods in a day when it is determined that the carbon dioxide emission coefficient of the electricity is equal to or smaller than the carbon dioxide emission coefficient of the fuel.

[0151] With the hybrid air conditioning system 10 configured as described above, the engine 20 or the motor (motor generator 21), whichever has the smaller carbon dioxide emission coefficient, is used preferentially as the driving power source for the compressors 22a and 22b, thereby reducing carbon dioxide emissions compared to when such control is not performed. Therefore, it is possible to provide a hybrid air conditioning system 10 that can contribute to reducing carbon dioxide emissions.

[0152] (2) The carbon dioxide emission coefficient for the electricity can be a marginal coefficient during a first time period, which is a time period from evening to night, and can be a total power source coefficient during a second time period, which is a time period other than the first time period.

[0153] According to this configuration, by taking into account the use of renewable energy, it is possible to appropriately estimate the carbon dioxide emission coefficient associated with the use of electricity energy according to the time period.

[0154] (3) The first time period may include at least a part of the time period from 16:00 to 21:00.

[0155] With this configuration, the marginal coefficient can be used in an appropriate time period as the carbon dioxide emission coefficient associated with the energy use of electricity. Note that, although the above embodiment shows an example in which the first time period is the time period from 16:00 to 21:00, the first time period need only include at least a part of the time period from 16:00 to 21:00, and is not limited to a time period that includes the entire time period from 16:00 to 21:00.

[0156] (4) In the hybrid air conditioning system 10 according to this embodiment, The compressors 22a and 22b include a first compressor 22a and a second compressor 22b, The control device 15 When the operating mode is the carbon dioxide emission saving mode, if it is determined that the air conditioning load is small during the engine priority time period, one of the first compressor 22a and the second compressor 22b is operated by the driving force of the engine 20, if it is determined that the air conditioning load is small during the motor priority time period, one of the first compressor 22a and the second compressor 22b is operated by the driving force of the motor (motor generator 21), and if it is determined that the air conditioning load is large during the engine priority time period or the motor priority time period, the engine 20 and the motor (motor generator 21) are controlled so that both the first compressor 22a and the second compressor 22b are operated by the driving force of the engine 20 and the motor (motor generator 21).

[0157] With this configuration, when the air conditioning load is high during engine priority time periods and when the air conditioning load is high during motor priority time periods, air conditioning operation can be continued to correspond to the air conditioning load while reducing carbon dioxide emissions.

[0158] (5) In the hybrid air conditioning system 10 according to this embodiment, a generator that generates electricity using the driving force of the engine (20); the operation mode includes a power generation mode in which power is generated by the generator, The control device 15 can be configured such that, when the operating mode is the power generation mode, the compressors 22a, 22b are operated by the driving force of the engine 20, and the generator generates electricity by the driving force of the engine 20.

[0159] In this power generation mode, air conditioning operation is performed using power generated by the generator, thereby reducing the amount of power supplied from the grid power supply used by the hybrid air conditioning system 10. Alternatively, the hybrid air conditioning system 10 can perform air conditioning operation without using power supplied from the grid power supply. Therefore, when the grid power supply is under pressure, the degree of pressure can be prevented or suppressed from increasing.

[0160] (6) In the hybrid air conditioning system 10 according to this embodiment, The motor (motor generator 21) is a power generating motor (motor generator 21), The control device 15 can be configured to control the engine 20 and the generator motor (motor generator 21) so that, when the operating mode is the power generation mode, the generator motor (motor generator 21) generates electricity using the driving force of the engine 20, and, when the operating mode is not the power generation mode, the generator motor (motor generator 21) provides driving force to the compressors 22a, 22b.

[0161] With this configuration, power can be generated without the need for a dedicated generator for power generation.

[0162] (7) In the hybrid air conditioning system 10 according to this embodiment, The compressors 22a and 22b include a first compressor 22a and a second compressor 22b, The operation modes include an engine mode in which the compressors 22a, 22b are operated only by the driving force of the engine 20, When the operation mode is the engine mode, the control device 15 can be configured to control the engine 20 so that when it determines that the air conditioning load is small, one of the first compressor 22a and the second compressor 22b operates using the driving force of the engine 20, and when it determines that the air conditioning load is large, it controls the engine 20 so that both the first compressor 22a and the second compressor 22b operate using the driving force of the engine 20.

[0163] In the engine mode, the motor (motor generator 21) is not used as a driving power source for the compressors 22a, 22b, which reduces the amount of power consumed by the grid power supply in the hybrid air conditioning system 10. Furthermore, if air conditioning operation is performed in the engine mode when the grid power supply is under a high level of power pressure, it is possible to prevent or suppress the grid power supply from becoming too tight.

[0164] (8) In the hybrid air conditioning system 10 according to this embodiment, The compressors 22a and 22b include a first compressor 22a and a second compressor 22b, The driving mode includes a hybrid mode, When the operating mode is the hybrid mode, the control device 15 can be configured to control the engine 20 and the motor (motor generator 21) so that, when it determines that the air conditioning load is low, one of the first compressor 22a and the second compressor 22b operates using the driving force of either the engine 20 or the motor (motor generator 21), and when it determines that the air conditioning load is high, it controls the engine 20 and the motor (motor generator 21) so that both the first compressor 22a and the second compressor 22b operate using the driving force of both the engine 20 and the motor (motor generator 21).

[0165] With this configuration, when the air conditioning load is low, either the engine 20 or the motor (motor generator 21) is used as the driving power source for the compressors 22a, 22b, which reduces the amount of electricity or gas used compared to when both are used.On the other hand, when the air conditioning load is high, both the engine 20 and the motor (motor generator 21) are used as the driving power source for the compressors 22a, 22b, which enables the air conditioning capacity to be achieved according to the user's needs.

[0166] (9) In the hybrid air conditioning system 10 according to this embodiment, When the operating mode is the hybrid mode, the control device 15 can be configured such that, when it determines that the air conditioning load is high, both the first compressor 22a and the second compressor 22b are operated by the driving force of either the engine 20 or the motor (motor generator 21), and when it determines that the air conditioning load is high and the driving force of either the engine 20 or the motor (motor generator 21) is insufficient, the control device 15 controls the engine 20 and the motor (motor generator 21) so that both the first compressor 22a and the second compressor 22b are operated by the driving force of both the engine 20 and the motor (motor generator 21).

[0167] With this configuration, even when the air conditioning load is high and both compressors 22a, 22b are driven, if the driving force of the engine 20 or the motor (motor generator 21) is sufficient, only one of the engine 20 and the motor (motor generator 21) is operated. This makes it possible to reduce the amount of gas or electricity used. On the other hand, if the driving force of the engine 20 or the motor (motor generator 21) is insufficient, both the engine 20 and the motor (motor generator 21) are operated, so that the driving force of the compressors 22a, 22b is not insufficient, thereby enabling the air conditioning capacity to be achieved according to the user's needs.

[0168] (10) In the hybrid air conditioning system 10 according to this embodiment, the hybrid mode includes an efficiency-priority mode that increases the energy consumption efficiency of the fuel or the electricity used, When the operating mode is the efficiency priority mode, the control device 15 can be configured to control the engine 20 and the motor (motor generator 21) so that when it determines that the air conditioning load is small, one of the first compressor 22a and the second compressor 22b operates using the driving force of the motor (motor generator 21), and when it determines that the air conditioning load is large, so that both the first compressor 22a and the second compressor 22b operate using the driving force of the engine 20 and the motor (motor generator 21).

[0169] With this configuration, air conditioning operation with high energy efficiency can be performed.

[0170] (11) In the hybrid air conditioning system 10 according to this embodiment, the hybrid mode includes a power saving priority mode that prioritizes reducing the amount of power used, The control device 15 When the operating mode is the power saving priority mode, the following configuration can be applied: when it is determined that the air conditioning load is small, one of the first compressor 22a and the second compressor 22b is operated by the driving force of the engine 20; when it is determined that the air conditioning load is large, both the first compressor 22a and the second compressor 22b are operated by the driving force of the engine 20; and when it is determined that the air conditioning load is large and the driving force of the engine 20 is insufficient, the engine 20 and the motor (motor generator 21) are controlled so that both the first compressor 22a and the second compressor 22b are operated by the driving force of the motor (motor generator 21) and the engine 20.

[0171] According to this configuration, when the operation mode is set to the power saving priority mode, the use of the motor (motor generator 21) is reduced, thereby reducing the amount of power used, which can contribute to power saving.

[0172] (12) In the hybrid air conditioning system 10 according to this embodiment, the hybrid mode includes a fuel saving priority mode that saves the fuel used, The control device 15 When the operating mode is the fuel saving priority mode, when it is determined that the air conditioning load is small, one of the first compressor 22a and the second compressor 22b is operated by the driving force of the motor (motor generator 21), when it is determined that the air conditioning load is large, both the first compressor 22a and the second compressor 22b are operated by the driving force of the motor (motor generator 21), and when it is determined that the air conditioning load is large and the driving force of the motor (motor generator 21) is insufficient, the engine 20 and the motor (motor generator 21) are controlled so that both the first compressor 22a and the second compressor 22b are operated by the driving force of the motor (motor generator 21) and the engine 20.

[0173] According to this configuration, when the operation mode is set to the fuel saving priority mode, the use of the engine 20 is reduced, thereby reducing the amount of gas used.

[0174] (13) In the hybrid air conditioning system 10 according to this embodiment, a generator (motor generator 21) that generates electricity using the driving force of the engine 20; The compressors 22a and 22b include a first compressor 22a and a second compressor 22b, the operation modes include the carbon dioxide emission saving mode, a power saving priority mode, an engine mode, a hybrid mode, and a power generation mode, The control device 15 When the operation mode is not the carbon dioxide emission saving mode, the hybrid mode is selected when the amount of electricity used by the air-conditioned object is less than a first threshold, the engine mode is selected when the amount of electricity used is equal to or greater than the first threshold and less than a second threshold that is a value greater than the first threshold, and the power generation mode is selected when the amount of electricity used is equal to or greater than the second threshold, When the hybrid mode is selected, if it is determined that the air conditioning load is small, one of the first compressor 22a and the second compressor 22b is operated by the driving force of either the engine 20 or the motor (motor generator 21), and if it is determined that the air conditioning load is large, it controls the engine 20 and the motor (motor generator 21) so that both the first compressor 22a and the second compressor 22b are operated by the driving force of both the engine 20 and the motor (motor generator 21); When the engine mode is selected, the engine 20 is controlled so that, when it is determined that the air conditioning load is small, one of the first compressor 22 a and the second compressor 22 b is operated by the driving force of the engine 20, and when it is determined that the air conditioning load is large, both the first compressor 22 a and the second compressor 22 b are operated by the driving force of the engine 20; When the power generation mode is selected, the compressors 22a, 22b are operated by the driving force of the engine 20, and the engine 20 is controlled so that the generator (motor generator 21) generates electricity by the driving force of the engine 20.

[0175] With this configuration, when the operating mode is not the carbon dioxide emission saving mode and the power supply is tight, the engine 20 is preferentially used as the driving power source for the compressors 22a and 22b, so that the power supply shortage can be prevented from worsening. Furthermore, the power supply shortage can be improved by the power generation by the generator (motor generator 21).

[0176] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. Various modifications of the present invention are possible without departing from the spirit of the present invention, and such modifications are also included in the scope of the present invention.

[0177] For example, in the above embodiment, the hybrid air conditioning system 10 is configured to include the motor generator 21, but is not limited to such a configuration. For example, the hybrid air conditioning system 10 may include a motor that is a driving power source for the compressors 22a, 22b, and a generator that is a separate device from the motor. In this case, the generator may be configured to generate electricity using the driving force of the engine 20. [Explanation of symbols]

[0178] 10... Hybrid air conditioning system, 11... Outdoor unit, 12... Indoor unit, 13... Refrigerant circuit, 14... Power unit, 15... Control device, 16... Battery, 20... Engine, 21... Motor generator, 22a, 22b... Compressor, 43... Outdoor heat exchanger, 44... Indoor heat exchanger

Claims

1. a refrigerant circuit including an indoor heat exchanger and an outdoor heat exchanger; an engine that generates driving force when fuel is supplied; a motor that generates driving force when supplied with power from a power system; a compressor that is operated by at least one of the driving force of the engine and the driving force of the motor, and that causes a refrigerant to circulate through the refrigerant circuit by operating; a control device that controls the engine and the motor, A hybrid air conditioning system including a carbon dioxide emission saving mode in an operation mode that reduces the amount of carbon dioxide emitted by using the fuel or the electricity, When the operating mode is the carbon dioxide emission saving mode, the control device controls the engine and the motor according to the time of day so that the compressor operates using the driving force of the engine during an engine priority time period, which is a time period during a day when it is determined that the carbon dioxide emission coefficient of the fuel is smaller than the carbon dioxide emission coefficient of the electricity, and so that the compressor operates using the driving force of the motor during a motor priority time period, which is a time period during a day when it is determined that the carbon dioxide emission coefficient of the electricity is equal to or smaller than the carbon dioxide emission coefficient of the fuel.

2. 2. The hybrid air conditioning system according to claim 1, A hybrid air conditioning system, wherein the carbon dioxide emission coefficient of the electricity is a marginal coefficient during a first time period that is preset as a time period from evening to night, and is a total power coefficient during a second time period that is a time period other than the first time period.

3. 3. The hybrid air conditioning system according to claim 2, A hybrid air conditioning system, wherein the first time period includes at least a part of a time period from 16:00 to 21:

00.

4. 3. The hybrid air conditioning system according to claim 2, the compressor includes a first compressor and a second compressor; The control device a hybrid air conditioning system that controls the engine and the motor so that, when the operating mode is the carbon dioxide emission saving mode and when it is determined that the air conditioning load is low during the engine priority time period, one of the first compressor and the second compressor is operated by the driving force of the engine, and when it is determined that the air conditioning load is low during the motor priority time period, one of the first compressor and the second compressor is operated by the driving force of the motor, and when it is determined that the air conditioning load is high during the engine priority time period or the motor priority time period, both the first compressor and the second compressor are operated by the driving forces of the engine and the motor.

5. 2. The hybrid air conditioning system according to claim 1, a generator that generates electricity using the driving force of the engine, the operation mode includes a power generation mode in which power is generated by the generator, When the operating mode is the power generation mode, the control device controls the engine so that the compressor is operated by the driving force of the engine and the generator generates electricity by the driving force of the engine.

6. 6. The hybrid air conditioning system according to claim 5, the motor is a generator motor, The control device controls the engine and the generator motor so that, when the operating mode is the power generation mode, the generator motor generates electricity using the driving force of the engine, and, when the operating mode is not the power generation mode, the generator motor provides driving force to the compressor.

7. 2. The hybrid air conditioning system according to claim 1, the compressor includes a first compressor and a second compressor; the operation modes include an engine mode in which the compressor is operated only by the driving force of the engine, When the operating mode is the engine mode, the control device controls the engine so that, when it determines that the air conditioning load is low, one of the first compressor and the second compressor is operated by the driving force of the engine, and when it determines that the air conditioning load is high, both the first compressor and the second compressor are operated by the driving force of the engine.

8. 2. The hybrid air conditioning system according to claim 1, the compressor includes a first compressor and a second compressor; The driving mode includes a hybrid mode, When the operating mode is the hybrid mode, the control device controls the engine and the motor so that, when it determines that the air conditioning load is low, one of the first compressor and the second compressor is operated by the driving force of either the engine or the motor, and when it determines that the air conditioning load is high, both the first compressor and the second compressor are operated by the driving force of both the engine and the motor.

9. 9. The hybrid air conditioning system according to claim 8, When the operating mode is the hybrid mode, the control device controls the engine and the motor so that, when it determines that the air conditioning load is high, both the first compressor and the second compressor are operated by the driving force of either the engine or the motor, and when it determines that the air conditioning load is high and the driving force of either the engine or the motor is insufficient, both the first compressor and the second compressor are operated by the driving force of both the engine and the motor.

10. 9. The hybrid air conditioning system according to claim 8, the hybrid mode includes an efficiency-priority mode that increases the energy consumption efficiency of the fuel or the electricity used, When the operating mode is the efficiency priority mode, the control device controls the engine and the motor so that when it determines that the air conditioning load is low, one of the first compressor and the second compressor is operated by the driving force of the motor, and when it determines that the air conditioning load is high, both the first compressor and the second compressor are operated by the driving forces of the engine and the motor.

11. 10. The hybrid air conditioning system of claim 9, the hybrid mode includes a power saving priority mode that prioritizes reducing the amount of power used, The control device When the operating mode is the power saving priority mode, the hybrid air conditioning system controls the engine and the motor so that when it is determined that the air conditioning load is low, one of the first compressor and the second compressor is operated by the driving force of the engine, when it is determined that the air conditioning load is high, both the first compressor and the second compressor are operated by the driving force of the engine, and when it is determined that the air conditioning load is high and the driving force of the engine is insufficient, both the first compressor and the second compressor are operated by the driving force of the motor and the engine.

12. 10. The hybrid air conditioning system of claim 9, the hybrid mode includes a fuel saving priority mode that saves the fuel used, The control device When the operating mode is the fuel saving priority mode, the hybrid air conditioning system controls the engine and the motor so that when it is determined that the air conditioning load is low, one of the first compressor and the second compressor is operated by the driving force of the motor, when it is determined that the air conditioning load is high, both the first compressor and the second compressor are operated by the driving force of the motor, and when it is determined that the air conditioning load is high and the driving force of the motor is insufficient, both the first compressor and the second compressor are operated by the driving forces of the motor and the engine.

13. 2. The hybrid air conditioning system according to claim 1, a generator that generates electricity using the driving force of the engine, the compressor includes a first compressor and a second compressor; the operation modes include the carbon dioxide emission saving mode, a power saving priority mode, an engine mode, a hybrid mode, and a power generation mode, The control device When the operation mode is not the carbon dioxide emission saving mode, the hybrid mode is selected when the amount of electricity used by the air-conditioned object is less than a first threshold, the engine mode is selected when the amount of electricity used is equal to or greater than the first threshold and less than a second threshold that is a value greater than the first threshold, and the power generation mode is selected when the amount of electricity used is equal to or greater than the second threshold, When the hybrid mode is selected, the engine and the motor are controlled so that, when it is determined that the air conditioning load is low, one of the first compressor and the second compressor is operated by the driving force of one of the engine and the motor, and when it is determined that the air conditioning load is high, both of the first compressor and the second compressor are operated by the driving force of both the engine and the motor; When the engine mode is selected, the engine is controlled so that one of the first compressor and the second compressor is operated by the driving force of the engine when it is determined that the air conditioning load is low, and so that both the first compressor and the second compressor are operated by the driving force of the engine when it is determined that the air conditioning load is high; When the power generation mode is selected, the hybrid air conditioning system controls the engine so that the compressor is operated by the driving force of the engine and the generator generates electricity by the driving force of the engine.

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